Figure 7.

Increased SMPDL3b expression is associated with the suppression of β₃ integrin, resulting in an apoptotic DKD-like phenotype in podocytes. (A) RhoA activity is significantly increased in human SMPDL3b OE podocytes and decreased in SMPDL3b KD podocytes compared with control podocytes (*P<0.05, control versus SMPDL3b KD podocytes; ^#P<0.05, control versus SMPDL3b OE podocytes). (B) Treatment of normal human podocytes with sera from patients with DKD leads to increased RhoA expression, and SMPDL3b KD podocytes are protected from DKD sera-induced increases in RhoA expression (*P<0.01). (C) suPAR treatment significantly increase apoptosis in SMPDL3b OE podocytes, whereas control and SMPDL3b KD podocytes are not susceptible to suPAR-induced apoptosis (*P<0.01). (D and E) Inhibition of β₃ integrin signaling renders (D) normal human podocytes susceptible to suPAR-induced apoptosis, whereas (E) SMPDL3b mRNA expression levels remain unchanged (*P<0.05). cRGD, cyclo-(Arg-Gly-Asp) peptide; GAPDH, glyceraldehyde-3-phosphate dehydrogenase.